Problem: $f(x) = 4x^{2}-g(x)$ $g(n) = -2n$ $ f(g(3)) = {?} $
Explanation: First, let's solve for the value of the inner function, $g(3)$ . Then we'll know what to plug into the outer function. $g(3) = (-2)(3)$ $g(3) = -6$ Now we know that $g(3) = -6$ . Let's solve for $f(g(3))$ , which is $f(-6)$ $f(-6) = 4(-6)^{2}-g(-6)$ To solve for the value of $f$ , we need to solve for the value of $g(-6)$ $g(-6) = (-2)(-6)$ $g(-6) = 12$ That means $f(-6) = 4(-6)^{2}-12$ $f(-6) = 132$